Tape indicia on clear film media

ABSTRACT

A print medium is encoded with information bearing indicia. A transparent layer or substrate which receives the printed information during printing has a first surface, a second surface and a leading edge. A strip of tape is applied to the first surface. A machine readable information bearing indicia is applied to at least one surface of the tape strip. The indicia is formed by a pattern of fluorescent material which upon excitation by radiation of a given spectral excitation range emits radiation in a fluorescent spectral range. The tape reflects radiation in the given excitation spectral range and in the fluorescent spectral range. In another embodiment, the strip of tape is applied to the first surface of the layer of the print medium, and has a top surface which is exposed when the tape strip is applied to the print medium and a bottom surface adjacent the first surface of the print medium. A first machine readable information bearing indicia is applied to the top surface of the tape strip. A second machine readable information bearing indicia is applied to the bottom surface of the tape strip. One type of indicia is a bar code pattern, although other types can also be employed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a continuation-in-part of application Ser. No. 08/868,020, filedJun. 30, 1997, in turn a continuation of application Ser. No.08/419,170, filed Apr. 10, 1995, now abandoned, in turn a division ofapplication Ser. No. 08/198,658, filed Feb. 18, 1994, issued as U.S.Pat. No. 5,428,384, in turn a continuation of application Ser. No.07/876,924, filed May 1, 1992 now abandoned.

This application is related to application Ser. No. ______, entitledTECHNIQUES TO PREVENT LEAKAGE OF FLUORESCING SIGNALS THROUGH PRINT MEDIAOR INDICIA TAPE, filed ______, attorney docket 10991745-1, and toapplication Ser. No. 09/328,543, filed Jun. 9, 1999, entitled SYSTEM ANDMETHOD FOR CONTROLLING AN IMAGE TRANSFER DEVICE, the entire contents ofwhich applications are incorporated herein by this reference.

TECHNICAL FIELD OF THE INVENTION

This invention relates to print media, and more particularly totechniques for marking clear or transparent film media with indiciareadable by an inkjet printer, copier, fax machine, large format printeror other printing mechanism.

BACKGROUND OF THE INVENTION

Inkjet printing systems are in widespread use today. Ink jet printersprint dots by ejecting very small drops of ink onto the print medium,and typically include a movable carriage that supports one or moreprintheads each having ink ejecting nozzles. The carriage traverses overthe surface of the print medium, and the nozzles are controlled to ejectdrops of ink at appropriate times pursuant to command of a microcomputeror other controller, wherein the timing of the application of the inkdrops is intended to correspond to the pattern of pixels of the imagebeing printed.

Color ink jet printers commonly employ a plurality of printheads, forexample four, mounted in the print carriage to produce different colors.Each printhead contains ink of a different color, with the commonly usedcolors being cyan, magenta, yellow, and black. Printing devices may haveseveral features or other options, such as print speed, driverselection, dry time and print mode.

Printing devices, such as inkjet printers, use printing composition(e.g.,ink or toner) to print text, graphics, images, etc. onto printmedia. The print media may be of any of a variety of different types,sizes, side-specific coatings, etc. For example, the print media mayinclude paper, transparencies, envelopes, photographic print stock,cloth, plastic, vinyl, special material, etc. Each of these types ofprint media have various chemical and physical characteristics thatideally should be accounted for during printing; otherwise less thanoptimal printed products may occur. Additional characteristics may alsoaffect print quality, including print medium size print mediumorientation, and print medium sideness.

One way in which a printing device can be configured to a particularprint medium is to have a user make manual adjustments or make programinputs to the printing device based upon these characteristics andfactors. One problem with this approach is that it requires userintervention which is undesirable. Another problem with this approach isthat it requires a user to correctly identify various characteristics ofa particular print medium which the operator may not know. A furtherproblem with this approach is that a user may choose not to manuallyconfigure the printing device or may configure the printing deviceincorrectly so that optimal printing still does not occur in spite ofuser intervention. This can be time-consuming and expensive depending onwhen the configuration error is detected and the cost of the particularprint medium.

It would therefore be an advantage to be able to automatically readmedia characteristic information automatically and without requiringuser input, by having the media communicate directly to the printingdevice.

Inkjet printers can support printing images on a variety of print mediatypes, including plain paper, coated paper, clear film media, as well asothers. There are several known methods for marking paper media withmachine readable indicia, including visible indicia and indicia notvisible to the human eye under normal ambient lighting conditions.

Readable indicia on clear film can be printed to be visible or invisibleto humans. Compounds which reflect or fluoresce light at non-visiblewavelengths will still be slightly visible to humans. This visibility iscaused, e.g., by a difference in the refractive index of the compoundand the clear film.

Indicia typically includes marks on a media substrate that eitherabsorb, reflect or emit light. In all cases, for an indicia to bemachine readable, there must be enough difference in radiation returnedfrom marked areas of indicia and unmarked areas on the substrate that auseful signal is generated.

Indicia placed on clear film are difficult to read using an opticalsensor. With a clear background, as in the case of clear film, a poorcontrast is produced between the indicia and the background. If theindicia are made to absorb light, they cannot be detected at all. Clearfilm reflects only a small portion of the incident light. Placing alight absorbing compound on the indicia only causes this small portionof reflected light to be absorbed. The difference in signal is wellbelow the noise level. If fluorescing indicia are used, then the levelof fluorescence is greatly reduced by a clear background. Thisdifference in signal strength is shown in FIGS. 1A and 1B, showing therespective situations when a fluorescent material is placed on thesurface of a sheet of white paper and on clear film. With the whitepaper, most of the incident and fluorescent light is reflected upwardly.Some of the reflected fluorescent light will enter the sensor to providesignal. With the clear film, a large portion of the incident andfluorescent light will not be reflected up to the sensor. The light willeither pass through the film (D) or be lost to total internalreflection.

A white background can be placed in the printer behind the clear filmmedia at a point where the indicia will be read by the sensor. Thishelps to create a contrast, but fluorescing compounds still produce apoor signal due to the inefficiencies illustrated in FIG. 1. The smallair gap between the clear film and the white background will create aninterface at which significant light will be lost.

SUMMARY OF THE INVENTION

One embodiment of a print medium encoded with information bearingindicia includes a transparent layer of a print medium having a firstsurface and a second surface and a leading edge. A strip of tape isapplied to the first surface of the layer of the print medium. A machinereadable information bearing indicia is applied to a surface of the tapestrip. The indicia is formed by a pattern of fluorescent material whichupon excitation by radiation of a given spectral excitation range emitsradiation in a fluorescent spectral range. The tape reflects radiationin the given excitation spectral range and in the fluorescent spectralrange.

In another embodiment of the invention, a print medium is encoded withinformation bearing indicia, and includes a transparent layer of a printmedium having a first surface and a second surface and a leading edge. Astrip of tape is applied to the first surface of the layer of the printmedium, the tape strip having a top surface which is exposed when thetape strip is applied to the print medium and a bottom surface adjacentthe first surface of the print medium. A first machine readableinformation bearing indicia is applied to the top surface of the tapestrip. A second machine readable information bearing indicia is appliedto the bottom surface of the tape strip. The indicia can be formed byfluorescent material, readable by a detector system. One type of indiciais a bar code pattern, although other types can also be employed.

BRIEF DESCRIPTION OF THE DRAWING

These and other features and advantages of the present invention willbecome more apparent from the following detailed description of anexemplary embodiment thereof, as illustrated in the accompanyingdrawings, in which:

FIGS. 1A and 1B are diagrammatic views illustrating respectively thedifference in signal strength between a fluorescing material on whitepaper and the same material on a clear film.

FIG. 2 is a schematic diagram illustrative of an ink jet printersupporting printing using the new print media.

FIG. 3 is a top view of a transparent print media having an opaque tapealong the leading edge thereof.

FIGS. 4A-4C are respective top, bottom and cross-section views of aclear film print medium embodying this invention.

FIGS. 5A-5E illustrate respective alternate embodiments of a printmedium embodying the invention, wherein a tape is adhered along the topfront edge of a flat surface of a sheet of clear film.

FIG. 6 is a top view of another embodiment of a transparent printmedium, wherein the indicia-bearing opaque tape is disposed along, butspaced from, the leading edge.

FIG. 7 is a top view of another embodiment of a transparent printmedium, wherein the indicia-bearing opaque tape is disposed along, butspaced from, a lateral edge of the print medium.

FIG. 8 is a simplified block diagram of a printer system with a sensorcapable of reading the indicia and with indicia interpreting logiccapable of interpreting the indicia and controlling printer operations.

FIG. 9 is a schematic frontal view of a printer employing roll media,which printer is adapted to employ the invention hereof.

FIG. 10 is a perspective view of a roll of transparent film media whichbears an indicia-bearing opaque tape in accordance with the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A sheet-fed printer in accordance with an aspect of this inventionsupports a special transparent polyester medium. An exemplary inkjetprinter 50 is illustrated in FIG. 2. The printer 50 includes a mediaadvance apparatus for driving the print medium in the x direction, and acarriage scan apparatus for controlling the movement of a carriage,indicated generally as element 52 in FIG. 2, in the y direction(orthogonal to the plane of FIG. 2), in order to direct ink from the inkcartridges, shown generally as elements 54, onto a print medium at theprint region 56. In this embodiment, the printhead 52 supports four inkcartridges for black, yellow, magenta and cyan inks, respectively. Thisembodiment achieves acceptable color print quality on plain paper media,even using a print resolution of 300 dots per inch. The printhead andits operation are described more fully in the commonly assignedco-pending application entitled “STAGGERED PENS IN COLOR THERMAL INK-JETPRINTER,” May 1, 1992, Ser. No. 07/877,905, by B. W. Richtsmeier, A. N.Doan and M. S. Hickman, the entire contents of which are incorporatedherein by this reference.

The ink cartridges 54 each hold a supply of water-based inks, to whichcolor dyes have been added. One exemplary ink formulation for use in theheated printing environment of this exemplary printer is described inco-pending application Ser. No. 07/877,640, filed May 1, 1992, entitled“Ink-Jet Inks With Improved Colors and Plain Paper Capability,” assignedto a common assignee with the present invention, the entire contents ofwhich are incorporated herein by this reference. This invention is alsouseful in printers which do not employ a heated print zone environment.

The print medium in this embodiment is supplied in sheet form from atray 58. A pick roller 60 is employed to advance the print medium fromthe tray 58 into engagement between drive roller 62 and idler roller 64.Exemplary types of print medium include plain paper, coated paper,glossy opaque polyester, and transparent polyester. One exemplarytechnique for advancing the print medium is described in U.S. Pat. No.4,990,011, the entire contents of which are incorporated herein by thisreference.

The printer operation is controlled by a controller 10, which receivesinstructions and print data from a host computer 30 in the conventionalmanner. The host computer may be a workstation or personal computer, forexample. The user may manually instruct the controller 10 as to the typeof print medium being loaded via front panel medium selection switches32. In this exemplary embodiment there are three switches 32, one forplain paper, one for coated paper (e.g., Hewlett-Packard special paper),and another for polyester (clear or transparent film). The front panelswitch selection data is overridden if the data received from the hostcomputer includes medium type data.

Once the print medium has been advanced into the nip between the driveand idler rollers 62 and 64, it is advanced further by the rotation ofthe drive roller 62. A stepper drive motor 92 is coupled via a geartrain to roller 62 to drive the rollers 60, 62, 100 and 103 which drivethe medium through the printer media path.

The print medium is fed to a print zone 56 beneath the area traversed bythe cartridges 54 and over a print screen 66 which provides a means ofsupporting the medium at the print position. The screen 66 furtherallows efficient transfer of radiant and convective energy from theprint heater cavity 71 to the print medium as well as providing a safetybarrier by limiting access to the inside of the reflector 70.

While the medium is being advanced, a movable drive plate 74 is liftedby a cam 76 actuated by the printhead carriage. Once the print mediumreaches the print zone 56, the drive plate 74 is dropped, holding themedium against the screen 66, and allowing minimum spacing between theprint nozzles of the thermal ink-jet print cartridges and the medium.This control of the medium in the print zone is important for good printquality. Successive swaths are then printed onto the print medium by theink-jet head comprising the different print cartridges 54.

A print heater halogen quartz bulb 72 disposed longitudinally under theprint zone 56 supplies a balance of thermal radiation and convectiveenergy to the ink drops and the print medium in order to evaporate thecarrier in the ink. This heater allows dense plots (300 dots per inch inthis embodiment) to be printed on plain paper (medium without specialcoatings) and achieve satisfactory output quality in an acceptableamount of time. The reflector 70 allows radiated energy to be focused inthe print zone and maximizes the thermal energy available.

The printer 50 further includes a crossflow fan 90 located to direct anair flow from in front of the print zone to the print zone, to aid indrying inks and directing carrier vapors toward the evacuation duct 80for removal.

An evacuation duct 80 leads to an evacuation fan 82. The duct definesthe path used to remove ink vapors from around the print zone 56. Theevacuation fan 82 pulls air and vapor from around the print zone intothe duct 80 and out an evacuation opening. Evacuation of the ink vaporsminimizes residue buildup on the printer mechanism.

An exit roller 100, starwheels 102 and an output stacking roller 103work in conjunction with the heated drive roller 62 to advance and ejectthe print medium. The gear train driving the gears is arranged such thatthe exit roller drives the medium slightly faster than the roller 62 sothat the printer medium is under some tension once engaged by the exitroller. The frictional force between the print medium and the respectiverollers is somewhat less than the tensile strength of the print mediumso there is some slippage of the print medium on the rollers. Thetension facilities good print quality keeping the print medium flatunder the print zone.

The operation of the various elements of the printer 50 is controlled bycontroller 10. A thermistor 12 is provided adjacent the drive roller 62to provide an indication of the temperature of the roller 62 surface.Power is applied to the preheat bulb 14 disposed within the roller 62via a power measurement circuit 16, permitting the controller to monitorthe power applied to the bulb 14. Power is also supplied to the printheater bulb 72 via a power measurement circuit 18, permitting thecontroller to monitor the power level supplied to the bulb 72. Aninfrared sensor 20 is mounted adjacent the print zone on the printhead52, and is used to detect the edges of the print medium and whether themedium is transparent in order to select the appropriate operatingconditions for the print heater.

The printer 50 supports a special transparent polyester medium 106illustrated in FIG. 3, wherein a white opaque strip 110 about 0.5 incheswide is adhered to the back of the medium 110, i.e. the side that is notprinted on, along its leading edge 108, extending across the width ofthe medium. The infrared sensor 20 located on the carriage 54 detectsthe presence or absence of the strip. By advancing the leading edge ofthe medium more than 0.5 inches past the sensor, the sharp reduction inenergy reflected back to the sensor as the white strip is advancedbeyond the sensor indicates that the medium is transparent. The whitestrip is also used by the sensor to detect the width of the transparentmedium. Such an embodiment is particularly useful for sheet-fed ink-jetprinters, for example, which support the use of sheets of print mediumof a predetermined length. Thus, the printer device 50 locates the sheetleading edge and lateral edges, and can determine the trailing edgeposition from knowledge of the predetermined length. The printer 50employs a carriage-mounted optical sensor 20, since the sensor can beemployed to detect the advancement of the leading edge of the printmedium in the manner just described, and some printers can also detectthe location of the lateral edges by scanning the carriage across theprinter swath range of movement, and noting the locations at which thesensor output changes significantly.

FIGS. 4A-4C illustrate an exemplary alternate embodiment of a printmedium embodying the invention, wherein a tape 152 is adhered along thetop front edge 150A of a flat surface 150B of a sheet 150 of clear film.The film is adapted for use as a print medium in an ink jet printer. Thesheet surface 150C is the surface that receives the printing or inkdroplets during media imaging. The tape with the preprinted indicia ison the leading edge of the transparent media on the opposite side. Thetape has been placed on the side which will not receive the image. Thetape is up when the media is placed in the input tray. As the sheet isdrawn in and rotated 180 degrees around the feed roller, the indiciaprinted on the bottom of the tape, next to the media, is read. The mediais in proper position to be printed.

In an exemplary embodiment of this invention, light is emitted byfluorescence from the marked areas of the substrate in response toillumination from a sensor system such as is shown in FIG. 1A, includinga light source 120 and sensor 122. If the substrate used to support thefluorescing dye is black, it will absorb that portion of light which isemitted down into the substrate. If the substrate is clear, an evenhigher percentage of the light is lost through total internal reflectionwithin the substrate and other physical processes. If the substrate iscapable of reflecting the fluoresced light, a substantial increase insignal is obtained as the fluoresced light is reflected back towards thesensor. By reflecting light with the substrate, the signal to noiseratio of the sensing system is thus greatly improved.

FIGS. 4A and 4B are top and bottom views of the sheet, and FIG. 4C is apartial diagrammatic cross-sectional view of the sheet taken throughline 4C-4C of FIG. 4A. The tape 152 has a back surface 152A and a frontsurface 152B. A layer 154 of adhesive is used to adhere the tape to thesurface 150B of the film; preferably the adhesive is an opticallytransparent material. Machine readable indicia illustrated as layer 156in FIG. 4C are placed on the back surface 152A of the tape. The tape hasbeen preprinted with the indicia on both sides, shown as layers 156 and158. During production of the transparent media or film, the preprintedtape is applied with an adhesive 154 and fastened to the film prior toslitting or sizing of the film. The tape is applied to the top or frontside 150B of the media. This is the top side during production of thetransparent media, which becomes the non-imaged side. As the film, 150,is rotated 180 degrees around the feed roller, the indicia 158 is sensedand interpreted by the sensor. The film 150 is in proper orientation toallow imaging on the proper side 150C. The tape is made of material,e.g., paper, polyester, metalized polyester, polycarbonate,polyethylene, cellulose acetate butyrate, cellulose nitrate, that meetsthe specifications of infrared reflection required for the sensoroperation in this exemplary embodiment, and will typically be white.Other colored tapes can alternatively be used, e.g., magenta, but shouldnot absorb IR in this embodiment.

Typically the indicia 156, 158 on the tape will be of a nature that theyare virtually invisible to humans, but visible to or readable bymachines. In particular, the indicia may be composed of a compound thatis infrared fluorescent, near-infrared fluorescent or ultra-violetfluorescent. The geometry of the indicia is typically a bar-code.

As used in this description of the invention, “invisible” indiciainvolve a broad class of material formulations which cannot be seen bythe unaided eye when applied to a substrate and viewed with “natural”light (e.g. light from the sun) or light from conventional incandescentlamps and the like. Both of these light forms (as well as other formswhich are normally used for general illumination purposes in home,businesses and like) are collectively characterized as “white” lightwhich involves a combination of all the various colored light componentswhich fall within a wavelength range of about 400-700 nm. Under theseillumination conditions, the invisible indicia are essentiallycolorless. Only after illumination do the printed images becomedetectable (either with or without auxiliary observation equipment).

Suitable inks are known which can be used to form or apply the indiciaon the tape or film surfaces. The inks can be water-based or UV basedwith added IR dyes. The IR dyes are required in sufficient concentrationin the ink compound to provide adequate signal strength for reliabledetection by the sensor. Also, the UV dye, when illuminated by UVradiation of appropriate intensity, gives off a visible emission whichcan be read by a sensor. Visible light is electromagnetic radiation fromabout 400 nanometers (nm) to about 700 nm. Radiation in the range of 700nm to 1100 nm is typically called “near infrared radiation.”

An infrared (“IR”) dye which when illuminated by red light energy (600nm to 900 nm) of appropriate intensity gives off an emission which isdetectable by a sensor to provide an image of the barcode. Inks suitablefor the purpose are described in co-pending application entitled LIGHTSENSITIVE INVISIBLE INK COMPOSITIONS AND METHODS FOR USING THE SAME,application Ser. No. 09/181,581, filed Oct. 28, 1998, the entirecontents of which are incorporated herein by this reference.

The indicia may be placed on the tape, front and back, prior to adheringthe tape to the film or after the tape has been adhered to the film.This can be done using an inkjet printhead, or by other printingprocesses such as flexographic, letterpress, rotogravure, etc.

The indicia on the tape may be printed to read either in the horizontaldirection, vertical direction, or at an angle. Moreover, the firstindicia 156 (FIG. 4C) can be applied at a different position as viewedfrom the sensor position than indicia 158. This permits the sensor todistinguish the first indicia from the second indicia.

Indicia is preferably printed on both sides of the tape to provideinformation to the sensor on the printer. The indicia, printed inbarcode format shown as 156 and 158, in FIG. 4C, provides informationthrough the sensor to the printer. If the film is inserted in the wrongway, an error or information message would be relayed to the operatorthrough the program, either to the printer screen or the computerscreen, that the film must be removed, turned over and reinserted intothe tray of the printer. This prevents printing on the wrong side of thefilm, preventing expensive waste. The indicia on the film, shown as 156or 158 in FIG. 4C, can be coded to indicate the correct side to printon, that this print medium is film, not other paper media, size of film,(A or A4, etc.), fast or slow dry, etc. Thus, the indicia, e.g.invisible barcoding, provides valuable information to the printer viathe special sensor that can eliminate human operator errors and materialwaste.

FIG. 5A illustrates a leading edge portion of the film 150 having thetape 152 applied thereto, with a diagrammatic depiction of indicia 156Ato show how the indicia can be formed as a bar code pattern along theentire width of the leading edge of the film. The indicia 156A here area series of lines running parallel to the leading edge of the film,possibly varying in width and spacing, depending upon the requirementsof the particular application, which can be read by a stationary sensoras the film is moved along a media path toward a print zone in an inkjetprinter. Thus, the arrow 160A indicates the read direction of theindicia.

FIG. 5B illustrates a leading edge portion of the film 150 having thetape 152 applied thereto, with a diagrammatic depiction of indicia 156B,showing the indicia formed as a bar code pattern along the entire widthof the leading edge of the film. The indicia 156B are a series of shortlines which are perpendicular to the leading edge of the film. Theindicia 156B can be read by a sensor mounted on a scanning carriageholding inkjet printhead(s) once the leading edge of the film has beenmoved along a media path to the print zone in the inkjet printer. Thecarriage can be moved along its scan axis in a scanning mode to read thebar code prior to commencing a printing operation on the film. Thus, thearrow 160B indicates the read direction of the indicia.

FIG. 5C illustrates a leading edge portion of the film 150 having thetape 152 applied thereto, with a diagrammatic depiction of indicia 156C,showing the indicia formed as a bar code pattern along the entire widthof the leading edge of the film. The indicia 156C are a series of shortlines running along the entire width of the film, which are oriented ona 45 degree diagonal relative to the leading edge of the film. Theindicia 156B (FIG. 5B) can be read by either a stationary sensor as inFIG. 5A, wherein the read direction is along arrow 160A, or by a sensormounted on a scanning carriage as in FIG. 5B, wherein the read directionis indicated by arrow 160B. Thus, the type 156C of indicia illustratedin FIG. 5C can support both the horizontal and vertical read directions.

Normally, when media is marked with indicia, the user expects the codeto be invisible, or nearly invisible. This is because the marks formingthe indicia will normally be in the margin on the final printed media.Thus, in these circumstances, if the marks are visible, they willdetract from the overall quality of the print. However, in the casewhere tape is applied to overhead transparency film, the tape isnormally printed with visible marks such as the part number of theproduct and the company logo, and so making the indicia marks invisibleis not needed.

The marks, e.g. in the form of dots forming squares, become more visibleas the concentration of fluorescent material is increased. For productssuch as the overhead transparency with indicia-bearing tape, it has beendiscovered that small dots of more intensely fluorescent material couldbe printed on the tape in a “checker board” pattern or indicia. Thechecker board indicia 156D, shown in FIGS. 5D and 5E, is arranged so thecode can be read with both a printer carriage scanning detector systemand a sensor located in a fixed position in the paper path of theprinter. Because the checker board pattern is preferably extremelysmall, there is less area for the sensor to detect. Preferably, thefluorescence intensity is higher with this checkerboard pattern, thanwith lines forming the bar codes shown in FIGS. 5A-5C. In order toobtain the same signal as conventional bar codes, the fluorescentintensity of the checker board squares is preferably higher by the ratioof detector viewed ink area in a bar code to the detector viewed inkarea in checkerboard. The marks may be somewhat visible, but since thesemarks are on tape and do not detract from the printed image on theoverhead transparency, they do not normally cause a problem for the enduser.

In the exemplary pattern of FIG. 5E, the squares 162 represent areas ofsolid fill of the fluorescent material, and are detected as ones, andmissing squares 166, i.e. data areas devoid of the fluorescent material,are considered as zeros. Of course, other codes could be employed, orthe ones and zeros reversed. Looking at this figure, the code is eitherread left to right or top to bottom. The pattern repeats along thedirection 160B, and is only one pattern deep along direction 160A. Thedirection 160B is the direction oriented along the leading edge, and socould be read by a sensor mounted on a scanning carriage. In thisexample, the code is an eight bit word, with an exemplary code 11011101illustrated. The code values are shown for illustrative purposes in FIG.5E, but would not need to be shown on the tape.

In order to optimize sensing over the view area of the sensor, thespacing of the squares and the size of the squares are considered. Foran exemplary detection system, good detection results were provided withpattern squares 162 having a 0.03 inch side dimension, separated by 0.01inch spaces 164. In general, the dimensions of the checker board and theview area of the detector are the key design variables in deciding howlarge the squares need to be and how far apart they should be spaced.

The media embodiments shown in FIGS. 4 and 5 are illustrated asemploying the indicia-bearing tape along the leading edge of thetransparent print medium. The tape can alternatively be placed in otherlocations, as long as it does not interfere with the printed image. Forexample, FIG. 6 shows a sheet 200 in which the indicia-bearing tape 204is placed along but spaced from the leading edge 202 of the sheet, in alocation outside the printing area, or in an area to receive inkdroplets during printing operations. FIG. 7 shows another alternative,wherein the sheet 210 has an indicia-bearing tape 214, placed along alongitudinal edge 212 of the transparent sheet. The indicia on both ofthese alternative embodiments can be read using the same type of sensorarrangements discussed above regarding the embodiments of FIGS. 5A-5E.

An exemplary technique of reading tape indicia on clear film mediaemploys special indicia placed on media with a special codingconfiguration, and a printer system with a sensor capable of reading theindicia and with indicia interpreting logic capable of interpreting theindicia and controlling printer operations. An exemplary printing system250 is shown in simplified block diagram form in FIG. 8. Here, thesystem includes a controller 252, sensor system 254, carriage drivesystem 256, media advance system 258 and inkjet printheads 260. Thecontroller in this exemplary embodiment is a microprocessor or ASIC,programmed to perform the functions to control elements shown in FIG. 8,in a manner known in the art. The controller 252 further is programmedto perform an indicia interpreting function 252A, in response to thesensor signals received from the sensor system 254, to read the dataencoded by the indicia, and to adjust or set operating parameters of theprinting system in response to the data for the particular medium 150.Thus, the controller 252 operates the media advance system to advancethe medium 150 from an input location past the sensor 254. The sensor254 is controlled to illuminate the medium with radiation of theappropriate wavelength range to excite the fluorescent ink forming theindicia, and to read the indicia in response to the excitation. Thecontroller interprets this indicia using logic function 252A, and thencan perform the printing on the medium, taking into account theinformation read from the indicia.

The above-referenced application entitled SYSTEM AND METHOD FORCONTROLLING AN IMAGE TRANSFER DEVICE describes an image transfer devicewhich can also use a print media in accordance with this invention.

While the invention has been described above in the context of an inkjetprinter or image transfer device which utilizes media in sheet form, theinvention can be applied to other types of printers, e.g. printers thatemploy roll media or folded media. FIGS. 9 and 10 illustrate an ink-jetplotter/printer which can use encoded transparent media as describedabove, but in roll form.

Referring to FIG. 9, printer 300 includes an inkjet printhead 302 whichtranslates along a pair of slider bars 304 and 306 across the width ofmedium 308. In the known manner, a controller 310, by control signalscauses printhead 302 to traverse along slider bars 304 and 306 and toeject ink droplets onto medium 308 which passes therebeneath. Media 308passes over a roll 311 which positions media 308 accurately beneathprinthead 302 for printing. Media 308 also passes over a cutter bar 312which, in cooperation with a cutter 314 (similar to a pizza cutter),enables a transverse cut to be made across medium 308.

Cutter 314 is mounted on a carrier 316 which is also mounted for slidingmovement along slider bars 304 and 306. When printhead 302 is moved intocontact with carrier 316, a coupling mechanism 318 enables carrier 316to move along with printhead 302 and to cut off a section of medium 308.

Referring to FIG. 10, a roll 320 of transparent medium 308 is shown,before mounting in printer 300. In an exemplary embodiment, the leadingedge of medium 308 includes an indicia-bearing tape 150, which canemploy for example any of the indicia illustrated in FIGS. 5A-5E. Theindicia can identify, for example, the media type and size, and length.Alternatively, or additionally, the tape 150 can be disposed along alongitudinal edge of the medium 308, as also shown in FIG. 10. In thislongitudinal orientation, the indicia can identify, in addition to themedia type and size, the remaining length of medium on the roll. Thus,at spaced intervals along the length, the indicia can identify aremaining length. With this arrangement, the remaining lengthinformation is readable by the printer controller, even after the rollhas been partially used, removed from the printer, and later reinstalledin the printer for subsequent use. The tape can be placed along bothlongitudinal edges of the medium 308 to provide mechanical stability onthe roll.

Sensor 324 (FIG. 9) is positioned to read the coded indicia formed ontape 150 as it passes thereover. Data read from the coded indicia is fedto controller 310, which stores the data in a memory 328. Controller 310then utilizes the data derived from the indicia to set parameters forcontrol of printer 300, e.g. in accordance with the media typeidentified by the coded indicia.

Controller 310 further causes roller 311 to move the medium 308 a shortdistance so that the tape 150 passes the cutter bar 312. Printhead 302is then moved to engage carrier 316. Thereafter, printhead 302 dragscarrier 316 and cutter 314 across the medium 308, cutting off theportion of medium 308 carrying the tape 150. Normal printing/plottingthen occurs. Alternatively, the tape can remain on the medium duringprinting, in an area which does not receive ink droplets.

A technique for marking transparent film print media with machinereadable indicia has been described. There are several advantages to thetechnique. A stronger signal is obtained from reading an indicia printedon a tape strip than reading an indicia on clear film with a whitebackground behind the film. An inexpensive, simple sensor may be used inthe printer, since the sensor does not need to be able to read indiciawith weak signal levels. Another advantage is that the same detectiontechnique can be used for detecting indicia on clear film and on opaque,white media. Yet another advantage is that it is not necessary toregister the position of the indicia on the sheet of film. If theindicia are printed continuously along the length of the tape, theindicia will always be readable, either in a vertical direction, ahorizontal direction, or in a diagonal direction. If the diagonal (45degree) indicia are used, the detection system in the printer can bedesigned to scan in either a horizontal or vertical direction. Thisgives printer designers the option of choosing either detectionstrategy.

It is understood that the above-described embodiments are merelyillustrative of the possible specific embodiments which may representprinciples of the present invention. Other arrangements may readily bedevised in accordance with these principles by those skilled in the artwithout departing from the scope and spirit of the invention.

1-33. (canceled)
 34. A method of reading data encoded on transparentprint media, comprising: providing a transparent layer of a print mediumhaving a first surface and a second surface and a leading edge, themedium including a strip of tape applied to the first surface of thelayer of the print medium, a machine readable information bearingindicia applied to a surface of the tape strip, the indicia formed by apattern of fluorescent material which upon excitation by radiation of agiven spectral excitation range emits radiation in a fluorescentspectral range, and wherein the tape reflects radiation in said givenexcitation spectral range and in said fluorescent spectral range;providing an image transfer device having a light source forillumination the tape strip and a sensor for detecting the radiationemitted by the indicia; and illuminating the indicia with the lightsource and detecting the radiation emitted by the indicia to read theinformation represented by the indicia.
 35. The method of claim 34wherein the transparent layer is in the form of a sheet.
 36. The methodof claim 34 wherein the transparent layer is in the form of a roll.37-39. (canceled)
 40. A method of reading data encoded on transparentprint media, comprising: feeding a transparent print medium into a mediapath of a printer, the print medium having a first surface and secondsurface and a leading edge, the medium including a strip of tape appliedto the first surface of the layer of the print medium, a machinereadable information bearing indicia applied to a surface of the tapestrip, the indicia formed by a pattern of fluorescent material whichupon excitation by radiation of a given spectral excitation range emitsradiation in a fluorescent spectral range, the tape reflecting radiationin said given excitation spectral range and in said fluorescent spectralrange; illuminating the indicia with radiation of said given spectralexcitation range; sensing the radiation in said fluorescent spectralrange to read the information represented by the indicia; and employingsaid information to control an operation of said printer.
 41. The methodof claim 40 wherein the transparent layer is in the form of a sheet. 42.The method of claim 40 wherein the transparent layer is in the form of aroll.
 43. The method of claim 40 wherein said second surface is forrecording printed information during a print process, and said strip oftape is applied to said first surface which is opposite to said secondsurface on which print information is recorded during the print process,and further comprising: operating the printer to record information onsaid second surface.
 44. The method of claim 40, further comprising anoptically transparent adhesive layer adding said strip of tape to saidfirst surface of the layer of the print medium.
 45. The method of claim40, wherein said tape is fabricated of a white material.